Inverse emulsions comprising avermectins and cosmetic/dermatological applications thereof

Abstract

Physically and chemically stable, oxidation-resistant, cosmetic/dermatological inverse emulsions contain a therapeutically effective amount of at least one avermectin compound, notably ivermectin, a glycolic or aqueous/glycolic dispersed hydrophilic phase, a continuous lipophilic phase and an emulsifier having an HLB ranging from 2 and 7, and are useful for the treatment of a variety of dermatological conditions/afflictions, e.g., rosacea.

1. A cosmetic/dermatological composition which comprises an inverse emulsion of a glycolic or aqueous/glycolic hydrophilic phase dispersed in a continuous lipophilic phase, said inverse emulsion comprising, as percentages by weight with respect to the total weight thereof, ivermectin in an amount of from 0.01% to 5%, glycols in an amount of from 30% to 70%, an emulsifier having an HLB ranging from 2 to less than 7 in an amount of from 0.5% to 8%, water in an amount of up to 25% and, optionally, a coemulsifier having an HLB of greater than 6 in an amount of up to 5%, said inverse emulsion being physically and chemically stable and oxidation-resistant. 
     
     
       2. The cosmetic/dermatological composition as defined by  claim 1 , devoid of DHEA and/or vitamin D derivative. 
     
     
       3. The cosmetic/dermatological composition as defined by  claim 1 , said ivermectin being dissolved in the dispersed glycolic or aqueous/glycolic phase. 
     
     
       4. The cosmetic/dermatological composition as defined by  claim 2 , comprising about 1% of ivermectin. 
     
     
       5. The cosmetic/dermatological composition as defined by  claim 1 , said emulsifier having an HLB ranging from 2 to less than 7 comprising a silicone emulsifier. 
     
     
       6. The cosmetic/dermatological composition as defined by  claim 1 , said emulsifier having an HLB ranging from 2 to less than 7 being selected from the group consisting of laurylmethicone copolyol, cetyldimethicone copolyol, a mixture of dimethicone copolyol and cyclomethicone, and a mixture of cetyldimethicone copolyol with polyglyceryl-4 isostearate and hexyl laurate. 
     
     
       7. The cosmetic/dermatological composition as defined by  claim 1 , wherein the coemulsifier having an HLB of greater than 6 is present. 
     
     
       8. The cosmetic/dermatological composition as defined by  claim 7 , wherein said coemulsifier comprises ceteareth-20. 
     
     
       9. The cosmetic/dermatological composition as defined by  claim 1 , wherein the proportion by volume of glycol, with respect to the total volume of the dispersed phase, ranges from 60% to 100%. 
     
     
       10. The cosmetic/dermatological composition as defined by  claim 1 , wherein the dispersed phase comprises at least one glycol selected from the group consisting of propylene glycol, hexylene glycol, dipropylene glycol and PEG 400. 
     
     
       11. The cosmetic/dermatological composition as defined by  claim 1 , formulated as a medicament. 
     
     
       12. A method for the treatment of rosacea, comprising administering to an individual in need of such treatment, a thus effective amount of the cosmetic/dermatological composition as defined by  claim 1 . 
     
     
       13. The cosmetic/dermatological composition as defined by  claim 1 , further comprising an adjuvant selected from the group consisting hydrophilic gelling agents, lipophilic gelling agents, humectants, fatty-phase thickeners, preservatives, antioxidants, electrolytes, solvents, fragrances, filters, screening agents, pigments, odor absorbers, coloring materials and metal-chelating agents. 
     
     
       14. The cosmetic/dermatological composition as defined by  claim 1 , further comprising an electrolyte. 
     
     
       15. The cosmetic/dermatological composition as defined by  claim 14 , wherein the electrolyte is magnesium sulfate heptahydrate.